Assuming a core plus valence nucleon structure, one-nucleon removal reaction is investigated within the framework of few-body Glauber theory. Fermi-type distribution is used for the core density, while the wavefunction of the valence nucleon is calculated by solving the single particle eigeuvalue problem of the SchrSdinger equation with the Woods-Saxon potential. The parallel momentum distribution (P//) of the fragments is calculated for isotopes with 3 < Z < 18. A remarkable scaling property is observed from the dependence of the dimensionless quantity R2v/R2c on the full width at half maximum of the parallel momentum distribution (FWHMp//). R2v/R2c is a measure of the exotic extent of the nuclear halo. Based on the obtained scaling law, FWHMp// can be used as an experimental observable to extract R2v/R2c and measure the exoticextent for the nuclear halo.